Marine diesel lubricant



. has not proved to be wholly effective.

United States Patent 2,944,022- MARINE DIESEL LUBRICANT No Drawing. Filed July 9, 1956, Ser. No. 596,400

3 Claims. (Cl, 25233.4)

This invention relates to lubricants for diesel engines. It is more particularly concerned with lubricants for marine diesels in which sour fuel oils are used as fuels. As is well known to those familiar with the art, many types of large marine diesel engines are lubricated by injecting small amounts of a lubricant into the cylinder during each cycle. Such engines do not have conventional case type of lubrication wherein the continuous, copious'lubrication of the pistons and cylinder walls is effected. As is further known, many of these engines bum fuels usually of the No. 6 Bunker fuel type that contain relatively large amounts of sulfur and other corrosive materials. As a result, when these oils are burned in the cylinder, there are formed quantities of corrosive acidic compound, such as sulfuric acid, sulfurous acid, etc. The

presence of'these materials is detrimental to the operational life of the engine because corrosion is increased and also because the presence of large amounts of strong acid promotes deposit formation and induces greater we of the piston and of the cylinder walls.

Accordingly, it will be appreciated that it would be highly advantageous to neutralize the acidic sulfur compounds; and to eliminatethe corrosive efiects thereof so that engine life can be prolonged. It is to be noted that the use of conventional high 'detergency lubricating oils Indeed, in the caseswhere such oils may be efiectivefit has been necessary to use such high concentrations of detergents that the overall-operation-is uneconomical; 7 A

lthas now been found that corrosion and wear in the operation of marine diesels can be reduced effectively and economically. It has now been discovered that the effects of harmful deposits in marine diesels can be overcome by lubricating-the engineswith a novel emulsion type lubricant that tends to neutralize acidic corrosive materials and to remove them from the combustion section of the engine; I

In; copending application Serial No. 561,344, filed January 25, 1956, which is a continuation-in-part of application Serial No. 541,847, filed October 20, 1955, and now abandoned, there was described a water-in-oil type emulsion lubricant for marine diesel engines that .con-. tained an alkali-metalhydroxide in the aqueous phase. In some cases, however, some lubricants prepared in accordance with these applications were lacking in emulsion stability. 7 r A It has now been found that extremely stable emulsion lubricants can be produced by a method that is simple and economically feasible. It has been discovered that very stable water-in-oil emulsion lubricants can be prepared bythe addition thereto of small amounts of certain fatty acids and by careful control of the amounts of the components of the lubricant. 1

Accordingly, it is an object of this invention to reduce corrosion in marine diesel operation. Another object is to provide a stable lubricant that will satisfactorily neu tralize acidic corrosive combustion products and remove them from the cylinder. A specific object is to provide r' r 2,944,022 latentedl 'l y 6 "2 a stable emulsion type lubricant that will overcome the harmful effects of corrosive agentswhile still maintaining elfective lubrication of a marine diesel engine. A more specific object is to provide a water-in-oil type emulsion lubricant that has alkali-metal hydroxide in the aqueous phaseand which is'stabilized'by addition'of small amounts of certain fatty acids and by careful control of the amounts of the components thereof. Other objects and advantages of this invention will become apparent to those skilled in. the art from the following detailed description.

In general, the present invention provides an emulsion type lubricant for marine diesels which comprises, by weight'of the lubricant, between about 10 percent and about 50 percent water (preferably between about 10 and about percent), between about 80 percent and about percent mineral lubricating oil (preferably between about 80 and about 55 percent), between about 1 percent and about 5 percent alkali-metal hydroxide, the amount thereof being sufiicient to efiect a total Base Number in the lubricant of between about 10 and about 100, between about 0.5 percent and aboutS percent oil-soluble deter gent, between about 3 percent and about 7 percent of an emulsifier that elfects water-in-oil type emulsion, and between about 0.5 percent and about 1 percent of a saturated fatty acid having 16 to 20 carbon atoms per molecule.

The lubricants of this invention are prepared by dissolving an alkali-metal hydroxide in the water and the oil soluble detergent in the mineral lubricating oil. The aqueous and the oil solution are then emulsified by the addition of a suitable water-in-oil type emulsifying agent by any conventional means. Thus, for example, the emulsion can be produced by agitation in any suitable homogenizing equipment, such as a Manton-Gaulin Homogenizer, a Stratco Contactor, or in a mechanically agitated,

' heated blending kettle. 1

The basic ma erials that. aredissolved in the aqueous phase of the lubricant re the alkali metal hydroxides. In general, hydroxide is preferred because of the lower molecular weight. I-Iowever, sodium and potassium des. ar efies ve- 'heam uu o a it vom" The mineral oil content of the lubricant of this invention will be the usual hydrocarbon lubricant utilizable for the lubrication of heavy machinery. Generally, this lubricating oil will be a petroleum hydrocarbon fraction or a blend of two or more fractions, of the No. 20 to No. 50 SAE grade. In terms of Saybolt Universal viscosity, the mineral oil will have a viscosity of 45-l00 seconds at 210 F., and preferably of -80 seconds at 210 F. The mineral lubricating oil can be obtained from any crude source or sources. It is especially preferred, however, to use a naphthenic oil, such as one obtained from a coastal crude. a

The detergents that are dissolved or dispersed in the oil phase are, in general, the additives'used in detergent motor oils. Usually they are polyvalent metal salts of organic acids. Nonlimiting examples include petroleum sulfonates, such as barium mahogany. sulfonate, magnesium petroleum su1fonate,.etc.; wax-substituted aryl sulfonates, such as barium di-wax benzene sulfonate, calcium tri-wa'x benzene sulfonate, barium waxnaphthalene sulfonate, etc.; sulfurized or unsulfurizedphenates and carboxylates, such as sulfurized calcium phenate, barium wax phenate, magnesium wax benzene carboxylate, etc, The detergents are not exactly equivalent and the selection of aparticular detergent will depend upon the emulsifier used. Some detergents 'will destroy the emulsion characteristics with Water.

7 f The mixture has the following characteristics; a f

' as sodium mahoganyfsulfonate, ammoniunimaphthalene sulfonate, etc. f esters of high molecular weight acids ob;

' tained by controlled oxidation of petroleum fractions} suchfas, wax;; fattyacid soaps, suchras sodium oleate;

- j redo" "soaps, potassium stearate, ammonium linoleate, 'etc.'; andthelikei 1 Thepreferred type of emulsifiersare anon-metallic material, such as theanimonium soaps ofithe various other ingredients of the'lubricant. The;

, effectiveness of an emulsifying-agent in any given formu-j latio'n can readily be determined by those skilled in the art by subjecting a sample'to an oven storage test at 170 F. LA stable emulsion lubricant will not separate,

. even after a month or more on this storage test;

1 As was mentioned hereinbefore, the emulsionlubricants of this invention are stabilized by the addition of small Fire o.c. t

'Further' details '7 as toi nature and properties of this Detergent Y, used herein, is'a calcium in'aho g any H sulfonate. A typical commercially available additive of this type is Lubriiol 12120, sold by theLubrizol Corp 7 Cleveland, Ohio M E Into a blending kettle equipped with a mechanical agitator, were placedS parts; by weight, of."Einulsifier X, 2 parts, by weight, ofrDetergent Y, and '60 parts, by weight, of a mineral lubricating oil '(Base OiLA), The mineral lubricating oil'is "a blend containing 38 vol; ume percent of a solvent refined coastal oil having a Saybolt viscosity of 150 seconds at 210 P. and 62' vol-l amounts of certain fatty acids These acids are the saturated fatty acids that contain between about 16 and about 20 carbon atoms per molecule, e.g., hexadecanoic acid,

stearic acid, and dodecanoic acid. Stearic acidis espe cially preferred. The concentration of added acid, based upbnithe weight of'the .totallubricant, mustbe between about 0.5 weight percent and about 1 weight percent.

i In order to obtain the stable emulsions of this invention,' the concentrations of the ingredients must be controlledlwithin certain It has been found that the components of the emulsion type lubricant of this invention can be varied are within the following ranges, based upon the weight of the finished lubricant: 1

'treme pressure) agents,,antioxidants, andthe like. The following examples are for the purpose ofillustrating the emulsion lubricants ofthisinvention and ofdemonstrating the etfectiveness thereof. It must be strictly understood; that the invention is not to bejestricted to the specific combinations described inthe ex:-

amples or to the operations and manipulations involved.

' rangeswithin which the concentration of the various to 3500 pounds p.s.i.g. Continuousagitation tained in the blending kettle while the emulsionwas'being' As those skilledjin the art willappreciate, other combi-L nations; as set forth hereinbefore, can be used. T

-Emulsifier, X, used in these examples, isa mixture of polyhydric alcohol esters of high molecular weight acids that is obtained bycontrolled oxidation of petroleum wax.

"A readily' available commercial. source of an emulsifier of this type is Alex l657,'sol d'by'the Alox Corp Niagara Falls, New York. s yp p or e i ggfAlox 1657"? has the follow 155 seconds Saybolt at 210 F; It'had'an'A;P.I.1grav ityi I Saybolt viscosity of 55 seconds at 210 F. This blend has an A.P.I. gravity of 24 degrees and a Saybolt vis-' cosity of about seconds at 210 F. The mixture of oil, detergent, and emulsifier" was heated with agitation at l30 F.,until the solution was complete. It was then cooled to -110" F; In a separate vessel was dissolved I three parts by weight of lithium hydroxide, monohydrate',

some emulsifiers, but will be found to be compatible with V Color V 7 Dark brown. others, l .7 f ,Ash ASTMD48246 f ,.0.07%.i-. I As has been mentioned hereinbefore, the oil phase and Melting pointASTMD-l2,7 49 F. the aqueous phase are maintained in-a stable water-im' V Viscosity@210? F 220-240 S.U.S.g' oil: emulsionby' means ofxasuitable emulsifyingTagenu 5 Specific gravity@ 146 F '0.874.

In general the emulsifyingagent'can'be a sulfona'te,fsuch Average weight per gallon t.. 7.3 lbs.

to obtain the emulsion. This emulsion wasthen'passed;

through a Manton-Gaulin Homogeni2eroperatedat 3000 transferred to thehomogenizer. 7 i 1 a i v I {11 water-in-oil emulsion lubricant thus produced thefollowing physical characteristics; V

SUS viscosity at -F. -g. SUSjviscosity at 210 F. Viscosity index V Total baseNo.ff 5' j This lubricant was placed aboard a commercial motoif vessel that'was powered with an 8' cylinder, 2 c cle,

'double acting .-Gotaverkin diesel engine. shiplwas operated continuously for .sevendaysi coastal voyage During' this time, .two cylinders were lubricated Withfth'e 1 emulsion lubricantof this example and six cylinders-wet lubricated with a standard marine lubricantof'the eral oil type. This oiltwas a blend of 57 volume percent T .solyent refined'coastaloilof 150 seconds Saybolt at2l0i I i F. and 43 volume percent solvent refined coastal'oiliof' I 1 of 24 and a Saybolt viscosity at 210 F. 0f 97 seconds."

At the completion of the run, it was found that the cylin l V ders lubricated with theremulsion type lubricantioper-f under testiss'tored in a'tall 4-02. bottle 'at F; The f sample is observed daily for sign's'of separation of the g emulsion. emulsion rated satisfactory (S), as to 7 stability, if there is no water separation and no more;

than atracetofoil separation visible after 30ida ys; unsatisfactory (U) emulsionfwill display visible signs afU separation being visible after one day, p

Base oil A 60 Water 30 Emulsifier X 4.5 Lithium hydroxide monohydrate 3.0 Detergent Y 2.0 Stcaric acid 0.5

When subjected to the aforedescribed stability test, this lubricant had a stability rating of S, no separation of emulsion occurring even after 66 days. In testing this lubricant in marine diesel installations aboard motor ships, it was found that excellent lubrication and protection of the engines against the effects of corrosive gases was achieved.

EXAMPLES 3 AND 4 Two emulsion lubricant formulations were prepared in accordance with the formulation described in Example 2, with the exception that the amount of stearic acid used was varied, together with the concentration of Emulsifier X. Pertinent variations from the formulation of Example 2 and emulsion stability test results are set forth in Table I.

Table I Stearlc Acid, Emulsifier Emulsion Example Parts by X, Parts Stability Wt. by Wt. Rating From the data of Table I, it will be appreciated that 0.25 part stearic acid, by weight, is insuflicient to impart stability to the emulsion. As noted from Example 2, 0.5 part is sufiicient, as is 1 part (Table I). Greater amounts of stearic acid failed to impart stability to the emulsion formulation. An emulsion stability rating of S was obtained with a formulation, as in Example 2, wherein palmitic (hexadecanoic) acid was substituted for the stearic acid. When, however, oleic acid was used, the emulsion was not stable. Therefore, the range of concentration of saturated fatty acid having between 16 carbon atoms and 20 carbon atoms falls within the relatively narrow range varying between about 0.5 part and about 1 part by weight of the finished lubricant.

In preferred practice, the stabilization of the emulsion lubricant is effected by replacing part of the emulsifier with a saturated fatty acid of 16-20 carbon-atoms. For example, if 5 parts of emulsifier is used in an emulsion formulation that proves to be unstable, the addition of 0.51 part fatty acid to stabilize it is accompanied by a corresponding reduction of emulsifier concentration, in this case from 5 parts to 4.5-4.0 parts.

The amount of emulsifier must also be controlled within limits. This will be apparent from the following examples.

EXAMPLES 5 THROUGH A series of emulsion lubricants was prepared using the formulation described in Example 2, with the exception that the concentration of Emulsifier X was varied, there being, however, no variation in the concentration of stearic acid or of the other components. The pertinent variations and corresponding emulsion stability test results of these lubricants are set forth in Table H.

Table II. r I. ';-.if. I Emulsifien: I Emulsion Example X, Parts Stability I" mby Wt. Rating 5 2 U. 6 3 "S". 7 1 4 8.. R 5 Se 9 7 S. 10 10 U.

From the data in Table H, it will be noted that poor emulsion stability results when the lubricant contains only 2 parts emulsifier and also when it contains as much as 10 parts, even with stearic acid present. On the other hand, stable emulsions are formed when the concentration of emulsifier is between about 3 parts and about 7 parts, by weight. Thus, it is another feature of this invention that the formulation must contain, together with 0.5-1 part fatty acid as aforedescribed, between about 3 parts and about 7 parts emulsifier, by weight; the emulsifier preferably being of the non-ionic type.

This application is a continuation-in-part of copending application Serial No. 561,344, filed January 25, 1956, which is a continuation-in-part of application Serial No. 541,847, filed October 20, 1955.

Although the present invention has been described with preferred embodiments, it is to be understood that modifications and variations may be resorted to, without departing from the spirit and scope of this invention, as those skilled in the art will readily understand. Such variations and modifications are considered to be within the purview and scope of the appended claims.

What is claimed is:

1. An emulsion lubricant for marine diesels which consists of, by weight of the lubricant, between about 10 percent and about 50. percent Water, between about 80 percent and about percent mineral lubricating oil, having a Saybolt Universal viscosity of between about 45 seconds and about 100 seconds measured at 210 F., between about 1 percent and about 5 percent alkali-metal hydroxide, the amount thereof being suflicient to effect a total base number in the lubricant of between about 10 and about 100, between about 1 percent and about 10 percent calcium petroleum sulfonate, between about-3 percent and about 7 percent of a mixture of polyhydric alcohol esters of high molecular Weight acids obtained by cont-rolled oxidation of petroleum wax, and between about 0.5 percent and about one percent saturated fatty acid having between 16 and 20 carbon atoms per molecule.

2. An emulsion lubricant for marine diesels which consists of, by weight of the lubricant, between about 10 percent and about 35 percent water, between about 80 percent and about percent mineral lubricating oil having a Saybolt Universal viscosity of between about seconds and about seconds measured at 210 F., between about 1 percent and about 5 percent lithium hydroxide, the amount thereof being sufiicient to effect a total base number in the lubricant of between about 10 and about 50, between about 1 percent and about 10 percentcalcium petroleum sulfonate, between aboutS percent and about 7 percent of a mixture of polyhydric alcohol esters of high molecular weight acids obtained by controlled oxidation of petroleum wax, and between about 0.5 percent and about 1 percent stearic acid.

3. An emulsion lubricant for marine diesels which consists of, by weight of the lubricant, about 30 percent water, about 60 percent naphthenic mineral lubricating oil having a Saybolt Universal viscosity of about'75 seconds measured at 210 F., 3 percent lithium hydroxide, 2 percent calcium petroleum sulfonate, about 4.5 percent of a mixture of polyhydric alcohol esters of high molecular weight acids obtained by controlled oxidation 

1. AN EMULSION LUBRICANT FOR MARINE DIESELS WHICH CONSISTS OF BY WEIGHT OF THE LUBRICANT, BETWEEN ABOUT 10 PERCENT AND ABOUT 50 PERCENT WATER, BETWEEN ABOUT 80 PERCENT AND ABOUT 45 PERCENT MINERAL LUBRICATING OIL, HAVING A SAYBOLT UNIVERSAL VISCOSITY OF BETWEEN ABOUT 45 SECONDS AND ABOUT 100 SECONDS MEASURED AT 210*F., BETWEEN ABOUT 1 PERCENT AND ABOUT 5 PERCENT ALKALI-METAL HYDROXIDE, THE AMOUNT THEREOF BEING SUFFICIENT TO EFFECT A TOTAL BASE NUMBER IN THE LUBRICANT OF BETWEEN ABOUT 10 AND ABOUT 100, BETWEEN ABOUT 1 PERCENT AND ABOUT 10 PERCENT CALCIUM PETROLEUM SULFONATE, BETWEEN ABOUT 3 PERCENT AND ABOUT 7 PERCENT OF A MIXTURE OF POLYHYDRIC ALCOHOL ESTERS OF HIGH MOLECULAR WEIGHT ACIDS OBTAINED BY CONTROLLED OXIDATION OF PETROLEUM WAX, AND BETWEEN ABOUT 0.5 PERCENT AND ABOUT ONE PERCENT SATURATED FATTY ACID HAVING BETWEEN 16 AND 20 CARBON ATOMS PER MOLECULE. 